- Practical advice
- Recreate the original moldings
- Around woodwork
- Headbands, cornices...
- To finish beautifully
- A zinc template for joinery moldings
- Project and scrape the plaster
- Realize the caliber
- Profiling the amounts
- In the formwork, a profiled zinc sheet
- Fix the formwork
- Pour the plaster
- Remove the formwork
- Place the molded headband
- Ensure the grip of the plaster
- Fix the formwork
- Vibrate the formwork
Two molding techniques have made it possible to restore the facade to its original moldings. Accessible in appearance, they do not require less a real twist!
Cost: About 200 e by window frame
Time: 1 to 2 days per window
Equipment: trough, trowel, nails, plaster wholesale, shuttering boards, zinc sheets, pegs...
Delicate to apply, the plaster requires a certain know-how! To facilitate its implementation, it can be added a little natural hydraulic lime or binder-glue for plaster tiles (about 1 flight for 5 plaster), to delay its setting and make it more flexible.
Recreate the original moldings
This home paired with simple rubble owes its character to the beautiful moldings that punctuate its facade: window and door frames, intermediate bands, corner chains, cornices... All are made of plaster from Paris.
With these remarkable qualities (microporosity, thermal and sound insulation, plasticity, aesthetics...), the plaster was naturally chosen to recreate the different moldings of origin, altered by time. Conducted at the same time as the three layers of plaster applied on the facade, this operation uses two techniques: one for the door and the windows, the other for the more substantial moldings (corner chain, decorative strips, cornices...).
The "caliber" technique consists of profiling moldings around windows and doors. Beforehand, it is necessary to make a wooden frame (planks of particle boards and cleats), from the readings of the moldings carried out before the staking of the plaster (our previous building site). Fixed around the bay, it forms a reservation that delimits the width and thickness of the molding to recreate.
The plaster is then projected into the reservation and then profiled using a "template" (a template formed of a zinc strip whose profile is made from the molding impressions taken during picketing).
Simple in principle, this method requires a true technical mastery. It must be advanced in short lengths to prevent the plaster "flows" or the caliber does not load plaster and produce beads.
The form casting technique is used to recreate larger structures that need to be molded into the mass such as window sills or decorative strips. A formwork boards and cleats is made from the dimensions of the original support. A profile zinc sheet is placed from the mold cavity.
After greasing its inner side to facilitate demolding, the formwork is fixed (at the base of a window for example), then filled with plaster. When the latter has made its decision, the form is removed and then fixed to the base of the next bay. The serial work is thus facilitated. At the end of the construction site, supports and strips are protected from run-off by a pre-patinated zinc strip. The joints are sealed with a polyurethane sealant.
To finish beautifully
In finishing, it is possible to apply two coats of whitewash on the moldings. Economic and natural, a whitewash is a protective and decorative paint that is obtained by mixing a volume of lime in two volumes of water (with possible addition of dyes such as pigments or ochres). But there are also ready-to-use products ("Badilit" and "Ravalith" by Cesa Saint-Astier, "Vixalit" by Lafarge, "Calcilane whitewash" by Parex...).
A zinc template for joinery moldings
A wooden frame is made from the records of the moldings before picketing the facade. Fixed around the bay, it defines the width and thickness of the decor to be recreated.
Project and scrape the plaster
Nails are planted in the reservation to hang the binder. The plaster is sprayed and scraped by sliding the edge of the trowel on the edge of the planks.
Realize the caliber
The template (template formed of a zinc strip for profiling the moldings) is made from the initial impressions. He is held with a firm hand to slide it along the frame.
Profiling the amounts
Same operation for the amounts. The profiling is done from bottom to top along the frame by moving in short lengths to prevent the caliber from loading plaster.
In the formwork, a profiled zinc sheet
At the bottom of the windows, a formwork made of planks and cleats is made to the dimensions of the original support. It receives a profiled zinc sheet according to the imprint of the molding.
Fix the formwork
The formwork is greased on the inside and then secured with pegs. After casting the plaster, it will be deposited and then be fixed against the base of the next window.
Pour the plaster
The rather liquid plaster is poured into the formwork (the catch accelerates by adding sand). When it is flush with the surface, it is trowelled to avoid bubbles and hollow areas.
Remove the formwork
When the plaster has set, the formwork is gently removed. Same operation for the realization of the decorative bands which surround the facade.
Place the molded headband
The windows of the floor are crowned by a molded headband. Its location is traced with a level and a large rule according to the readings made before work.
Ensure the grip of the plaster
Drilled holes along the lines in the coating layer facilitate the attachment of pegs. Nails are planted to ensure better grip of the plaster.
Fix the formwork
Made of a profiled zinc sheet like the original strip, the formwork is fixed by pegs and filled with plaster. It is deposited after one hour of drying.
Vibrate the formwork
Before the plaster has pulled, the formwork is "vibrated" by striking it with a hammer to raise the air bubbles to the surface and homogenize the filling.